Composition of matter



Patented June 17, 1941 UNITED STATES PATENT OFFICE COMPOSITION OF MATTERNo Drawing. Application February 1, 1940, Serial No. 316,778

4Claims.

This invention is directed to the stabilization of hydrocarbon oils ofhigher boiling points against the deteriorating effects of oxidation.Highly refined oils of the non-sludging types, such as the white oils,turbine ofls, and the like, must be able to withstand the conditions oftheir use without the formation of acidic constituents of a corrosive orotherwise damaging nature.

This invention contemplates the stabilization of such oils. Moderatelyrefined oils of the nature of many lubricant fractions must likewise beable to withstand the conditions of their use without the formation ofsludges, loss of color, or development of oxidation products corrosiveto commonly used metals, as for instance to copper. This inventionlikewise contemplates the stabilization of such moderately refined oils.In short, this invention is directed to the stabilization againstdeterioration due to oxidation reactions of any petroleum fractions of alight lubricant nature or heavier, from the lightest spindle oils,through the various classes of moderately refined oils of higherviscosity, and inclusive of the highly relilkned oils such as turbineofls, white oils, and the This invention has for an important object thepreparation of oils falling within the above classes which are stableagainst oxidation and capable of meeting the normal conditions of theiruse without the formation of gummy material, sludges, materials of anacidic or corrosive nature, and/or darker color. It also has for anobject the provision of a class of stabilizing materials not heretoforeknown to be effective for that purpose. a

Recent changes in automotive engine design, tending toward higherbearing pressures, higher rotative speeds, higher engine temperatures,and the like, have occasioned departure from the use of the usualbearing metals such as Babbitt. The newer bearing metals ar"fdii!erentnature, and, while harder, are in general more susceptible todestructive agencies of a corrosive nature. Typical of these newerbearings are those composed of a cadmium-silver alloy supported upon asteel back, which are now widely installed in certain makes ofautomobiles. Others of these relatively new bearing metals which may bementioned are" cadmium-nic eL and copper-lead alloys.

These changes in engine design have been concurrent with marked advancesin methods of refining lubricant oils for automotive use. The demand foroils having lesser changes in viscosity with temperature change: i. e.,higher viscosity index (V. 1.), has been met by refining lubricantsintended for motor oils by certain solvent-refining orsolvent-extraction processes, wherein advantage is taken of theselective solvent power i'or hydrocarbons of various types which ispossesed by certain liquid reagents-for example, dichlorodiethvi ether,cresylic acid, phenol, ichioraniline, chlorophenol, phenetidine, benzylalcohol, nitrobenzene, benzonitrile, furrural, aniline, benzi acetate,liquid sulfur dioxide, mixtures of liquid sulfur dioxide or aniline withbenzoi, and the like. These solvent-refining proceses are operated toconcentrate in the desired lubricant fraction those compounds of aparaiiinid' nature mof the ability to suffer only 8) small change ofviscosity upon change of temperature, and to reject the compounds of"naphthenic" nature which do suii'er such change of viscosity toa moremarked degree. These refining proceses have enabled supply of an oil ofquite desirable general characteristics, definitely far superior to anyoil previously produced from mixed base or asphaltic crudes, andsuperior to a like, though lesser, degree over oils previously producedfrom paraffin base crudes.

It has been found that the solvent-refined motor oils referred to aboveare for some reason definitelyvcorrosive to the newer bearing metalsunder normal conditions of automotive use, sometimes resulting inbearing failure after only a few thousand miles of normal driving. It isfurther known that the same reaction, viz., corrosion of alloy bearingmetals such as cadmiumsilver, occurs in good paraiilnic base oils whichhave not been subjected to solvent-refining. The higher the V. I. of thehbricatlm oil, the more mnoimced is the tendency to corrosion of thekind referred to above: generally speaking, the problem is encounteredin oils having a V. I. of or higher, and becomes important in oilshavingaV.I.ofto85orhigher. and very important in oils of V. I. orhigher.

It is an important object oi this invention to provide means forsatisfactorily inhibiting or preventing this corrosion from taking placeto a serious degree. It is an object of this invention to alter ormodify a highly refined motor oil, normally corrosive, by the use of anadditive ingredient capable of substantially inhibiting this corrosion.It is an object to provide a substantially non-corrosive motor oil ofhigh V. I. An object of this invention is to provide an additive reagentor ingredient. capable of inhibiting the corrosive properties of theseoils. The production of solvent-refined oils of low corrosive propertiesunder conditions of automotive use is a major object of this invention,as well as the method of production of such oils which couple highviscosity index with low tendency to corrosion.

We have found that hydrocarbon oils of the classes defined above can bestabilized in the respects above indicated by the additionthereto ofsmall amounts of compounds selected from the class of aryl phosphiteshaving the general formula (ArO):P, in which Ar designates an arylradical, as for instance CaHa or CHaCsI-Is. The aryl phosphites whichare suitable for the uses of this invention are as follows: Compounds ofthe general formula where one or more of the Rs is a radical selectedfrom the group consisting of where the R"s are radicals selected fromthe group consisting of hydrogen, alkyl, hydroxy', halogen, aryl (suchas phenyl and hydroxyphenyl), alkaryl, aikoxy, nitro, and amino andsubstituted amino (as phenyl or benzyl substituted).

,Of the above-defined classes of compounds, those at present preferredfor the uses of this inven-.

tion are those wherein all three Rs are radicals of either type (a) or(b) defined above, and wherein the R"s are either hydrogen or alkyl.Examples of specific materials which we have found especially suitablefor the uses of this invention are triphenyl phosphite, tricresylphosphltes, and tribeta-naphthyl phosphite; Where R is alkyl, it mayrange from a short alkyl such as methyl to very long alkylscorresponding, for example, to paraflin wax.

The general inventive concept as set forth in the preceding paragraph isembodied in our copending application Serial No. 106,227, of which thepresent application is a continuation in part. This application isspecifically directed to that class of the aforesaid compounds in whichR. is a long chain alkyl group corresponding to aliphatic hydrocarbonsof the type characterizing paraflin wax, These compounds, which we maydesignate as wax-aryl phosphites, distinguish over the general class ofphosphites described above in that they are efi'ective to reduce thepour point of viscous mineral oil fractions in addition to P improvingthe oil in the aforesaid respects. Thus, the wax or heavyalkyl-substituted aryl phosphites are multifunctional oil-additionagents, functioning as pour depressants and oxidation inhibitors whilethe aforesaid general class of aryl phosphites possess as their commonproperty that of corrosion or oxidation inhibition.

The specific compounds contemplated herein may be represented by thegeneral formula in which R represents a radical selected from the groupconsisting of hydrogen and the radicals wherein at least one R is a longchain alkyl radical corresponding to paraffin wax and the remaining R"sare radicals selected from the group consisting of hydrogen, alkyl,hydroxy, aryl, alkaryl, alkoxy, nitro, amino, and substituted aminoradicals, at least one of the Rs being selected from the aforesaid groupof radicals (a) (b) and (c). Of the compounds corresponding to theforegoing general formula preference is.

given to compounds of the type in which all of the R"s are substitutedwith aryl radicals, at least one of which has a long chain alkylsubstituent corresponding to an aliphatic hydrocarbon group of the typecharacerizing paraflln wax. Such preferred compounds may be identifiedas triaryl phosphites in which at least one of the aryl radicals has atleast one relatively long alkyl substituent of the general ordercorresponding to parafiin wax.

Triaryl phosphites of the character discussed above in which the arylradical is derived from phenol may be represented by the general formulawherein at least one R" is a long chain alkyl radical corresponding tothe alkyl radicals characterizing paramn wax and the remaining R"s areradicals selected from the group consisting oi hydrogen and alkyl.

.. blends are set forth in Table I below, wherein None- These wax-arylphosphites may be formed by first reacting a chlorinated paraflin wax orsimilar long chain aliphatic compound or predominantly aliphaticmaterial with a hydroxyaromatic compound, such as phenol, naphthol, andthe like, in the presence of a Friedel-Crafts catalyst to form awax-substituted phenol" or waxphenol" and then reacting the wax-phenolthus obtained with phosphorus trichloride.

For example, a so-called "monowax". phenol may be obtained by reacting aquantity of chlorinated paraflin wax (about 14 per cent chlorinecontent) with phenol in the presence of aluminum chloride, the reactionmixture being proportioned so that there is one atomic proportion ofchlorine present for each mol of phenol. By changing the ratio of thechlorwax to phenol in the reaction mixture so that there are two, threeor four atomic proportions of chlorine to one mol of phenol, theso-called di-, tri-, and tetra-wax phenols are obtained. TheFriedel-Crafts reaction for obtaining the wax-phenol is carried out atelevated temperature, preferably not to exceed 350 F.

The wax-phenol reacts with the PC13 at elevated temperature (from 103 F.to 205 F.) with the evolution of HCl gas. The use of a solvent such asethylene dichloride is desirable to reduce foaming. Following thereaction the mixture may be taken up in benzene containing a. littlefusel oil and washed with hot water, thereby hydrolizing any chlorine ofthe PC13 which has not been substituted with thewax-aryl nucleus.

EXAMPLE ONE Pom: POINT DEPRESSION The oil used in this test was an S. A.E. 30 motor oil having an A. S. T. M. pour point of +20 F. Severalblends of this oil were prepared with wax-phenyl phosphites of the typecontemplated herein and the pour points of such.

60 the various wax-phenyl phosphi-tes are identified Per Addition agentcan Monowax-phenok-PCP compound l. 0

EXAMPLE Two Gonnosron Inmnmon The oil usedinthistestwasan S.A.E.20-'motor oil having a specific gravity of 0.872, a flash point of 435 F.,and a Saybolt viscosity of 318 seconds at 100 F. The test involvedplacing a section of a. bearing containing a cadmiumsilver alloy surfaceand weighing about 6 grams inasampleof the oil andheatingtheoiltoatemperature of 175 C. for 22 hours while bubbling a stream of airagainst the surface of the bearing. The loss in weight of the bearing isa measure of the amount of corrosion which has From the foregoingexamples it will be seen that the wax-aryl phosphites contemplatedherein are effective to reduce the pour point and retard the deleteriouseffects of oxidation when added in minor proportions to viscous mineraloil fractions.

The amount of addition agent to be used will vary with the nature of theoil to be stabilized and with the use to which it will be put. Ingeneral, efiective stabilization and pour point depression will beobtained in the oils of the class herein discussed with not more than 2%of the wax-aryl phosphites, usually not more than 1%. For more commonuses, effective stabilization and pour point depression may be obtainedwith amounts in the neighborhood of 0.05 per cent to 0.50 per cent ofthese compounds.

In the claims, where the term hydrocarbonoils of relatively high boilingpoint or the equivalent thereof is used, it is intended to mean any andinclude all hydrocarbon mineral oil products normally used as lubricantsor for electrical insulating purposes. It includes oils with an S. U. V.of 50 seconds at F. or higher or a flash point greater than 200 F.(Cleveland open cup). This term, in efiect, is in contradistinction togasolines, kerosenes, and the like.

,As aforesaid, this application is a continuation in part of ourcopending application Serial No. 106,227, filed October 17, 1936, whichapplication is, in turn, a division of application Serial No. 46,870,filed October 26, 1935, now issued as Patent No. 2,058,343 of October20, 1936.

We claim:

1. As an antioxidant for petroleum hydrocarbon oil of boiling pointhigher than that of gasoline and kerosene, a triaryl phosphite in whichat least one of the aryl radicals has at least one relatively long alkylsubstituent of the general order corresponding to paraflin wax.

2. An improved mineral oil composition comprising a petroleum oil ofrelatively high boiling point normally tending to deteriorate byoxidation when heated and in admixture therewith a small proportion,suflicient to retard said deterioration and depress the pour point ofthe oil, of a triaryl phosphite in which at least one of the arylradicals has at least one relatively long chain alkyl substituent of thegeneral order corresponding to paraflln wax.

3. An improved mineral oil composition comprising a petroleum oil ofrelatively high boiling point, having added thereto a minor proportionof a compound or the general formula /-R P-O-R in which R. represents a.radical selected from the group consisting of hydrogen and the radicalspoint having added thereto a minor proportion of a compound of thegeneral formula wherein at least one R. is along chain alkyl radicalcorresponding to the aliphatic groups characterizing paraflin wax andthe remaining R"s are radicals selected from the group consisting ofhydrogen, alkyl, hydroxy. halogen, aryl, alkaryl, alkoxy, nitro, amino,and substituted amino radicals.

ROBERT C. MORAN.

WILLIAM L. EVERB. EVEREI'I W. FULLER.

CERTIFICATE OF CORRECTION. Patent No. 2,2h6,059. June 17, 19in.

ROBERT C. MORAN, ET AL.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows: Page 2,first column, line 55, and second column, lines 514. and 59, for "R s"read -Rs;

pageLp, first column, line 27, claim 5, for "R s" read -Rs-; and thatthe said Letters Patent should be read with this correction therein thatthe same may conform to the record of the case in the Patent Office.

.Signed and sealed this 6th day of January, A. D. l9b,2.

Henry Van Arsdale, (Seal) Acting Commissioner of Patents.

CERTIFICATE OF CORRECTION. Patent No. 2,21%,059. June 17, 19M.

ROBERT c. MORAN, ET AL.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows: Page 2,first column, line 55, and second column, lines 514. and 59, for "B s".read -Rs-;

pagelp, first column, line 27, claim 5, for "R s" read R s-; and thatthe said Letters Patent should be read with this correction therein thatthe same may conform to the record of the case in the Patent Office..Signed and sealed'this 6th day of January, A. D. 19m.

Henry Van Arsdale, (Seal) Acting Commissioner of Patents.

